(1) Field of the Invention
The present invention relates to a damper disk which may be used as clutch disks in clutches for automobiles, and particularly to a damper disk including two kinds of friction mechanism.
(2)Description of the Prior Art
The Japanese UtilitY Model Application No.59-200754 (Laid-Open Publication No.61-114130) commonly assigned to has disclosed a damper disk of a type mentioned above. In the structure disclosed in the above application, a pair of side plates, which are input members, are disposed at opposite sides of a flange of a hub, i.e., an output member, with first friction mechanisms therebetween. A pair of sub-plates are also arranged around the hub with said side plates and the flange therebetween, and second friction mechanisms are disposed between the sub-plates and side plates, respectively. In twisting motion, i.e., in relative rotating motion between the side plates and the flange during torque transmitting operation, sliding, which causes a small frictional force, is generated on the first friction mechanisms when the torsion angle or relative rotation angle is small, and sliding, which causes a large frictional force, is generated on the second friction mechanism, when the torsion angle is large.
The above structure, in which the frictional forces, and thus hysteresis torques in damping characteristics, change in accordance with the torsion angle, the torque vibration can effectively be absorbed through the entire extent of change of the transmitted torque, i.e., of torsion angle.
However, in the above known structure, a pair of the sub-plates are connected together by stud pins extending in an axial direction of the disk so as to apply a large compression force against the second friction mechanisms. Further, a pair of the side plates are supported bY sub-pins to maintain a predetermined space therebetween so that the compression force applied to the second friction mechanisms may not be applied through the side plates to the first friction mechanisms, and thus the frictional force on the first friction mechanisms may be maintained small.
This structure requires a pluralitY of the sub-pins in addition to the stud pins, and also requires apertures formed in the side plates, the flange and the first friction mechanisms for passing the sub-pins therethrough. The structure is therefore complicated and manufacturing process is also complicated.